SmogRank / Japan / Miyagi / Tome
Tome, month by month
Tome has a measured daily mean on 1,151 days since 28 July 2023. Its worst month was July 2025, at 54 US AQI (10.9 µg/m³), 1,070th of 2,889 cities on that month's world ranking. Its cleanest was December 2024, at 21 US AQI (3.8 µg/m³). 2025 averaged 39 US AQI (7.1 µg/m³), against 34 US AQI (6.2 µg/m³) in 2024.
Every month since 2023
The US EPA's Air Quality Index for PM2.5 (2024 breakpoints). Show values as: µg/m³ · US AQI · India AQI · China AQI · European AQI · UK DAQI · Canada AQHI+. About the scales
Months without a mean, and why
1 month
| Month | Why |
|---|---|
| Jul 2023 | 4 of 31 days measured; a month needs 22. |
A day counts once 18 hours of it are measured; a month needs 70% of its days.
Tome's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| July 2025 | 5410.9 µg/m³ | 1,070thof 2,889 | – |
| March 2025 | 529.8 µg/m³ | 1,625thof 2,862 | – |
| April 2024 | 519.3 µg/m³ | 1,107thof 2,520 | Japan and South Korea, April 2024 |
| March 2026 | 488.6 µg/m³ | 1,980thof 2,971 | – |
| June 2025 | 478.4 µg/m³ | 1,740thof 2,508 | – |
| May 2026 | 458.1 µg/m³ | 1,281stof 2,874 | – |
Monthly means over the days measured; finished months only. World rank: its place on that month's world ranking of every city with enough days. Each month opens that ranking.
Tome's worst days
| Day | US AQI | Episode |
|---|---|---|
| 18 Apr 2024 | 9231.0 µg/m³ | Japan and South Korea, April 2024 |
| 14 Feb 2026 | 7521.9 µg/m³ | – |
| 24 Nov 2025 | 7320.8 µg/m³ | – |
| 24 Mar 2026 | 7220.3 µg/m³ | – |
| 9 Jul 2025 | 7220.2 µg/m³ | – |
| 16 Jul 2026 | 7120.0 µg/m³ | – |
| 14 Mar 2025 | 7119.6 µg/m³ | – |
| 25 Mar 2025 | 7019.5 µg/m³ | – |
| 7 Jul 2025 | 7019.5 µg/m³ | – |
| 8 Jul 2025 | 7019.4 µg/m³ | – |
Daily means, the highest since 28 Jul 2023; the WHO's daily guideline is 15 µg/m³. Each date opens that day's world ranking, and each episode the bad-air spell it was part of.
Use this history
SmogRank, PM2.5 monthly and daily means, Tome, Japan, 28 Jul 2023 – 12 Oct 2026. Monitor data from Ministry of the Environment Air Pollutant Wide Area Monitoring System via OpenAQ; sources listed at smogrank.com/sources. smogrank.com/jp/tome/history (accessed 12 Oct 2026).
You're welcome to reuse a single chart, image or figure with this citation and a link. Terms. Raw monitor readings in bulk are published by OpenAQ, under each provider's licence.
Tome now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-12 19:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the US AQI PM2.5 sub-index. Some low-cost readings: Sensor.Community, ODbL (data and licence). Some readings: Uzhydromet (Uzbekistan's Hydrometeorological Service); Department of Environment, Nepal; Vietnam's government monitors; Aurassure; Umhverfisstofnun (Environment Agency of Iceland); RMCAB (Secretaría Distrital de Ambiente, Bogotá); Love My Air (City and County of Denver), no reuse terms published (why we use them).